Chapter 14 , 9class
tan inverse of( 2 cos (2 sin inverse of 1÷2))
interior angle bisector theorem
How v can easily learn tenses ...
Finalisation
P and Q can do a piece of work in 20 days and 12 days respectively. P started the work alone and then after 4 days Q joined him till the completion of the work. How long did it take for the work to be completed?